Rotary dental tool and method of manufacture

Abstract

A rotary dental tool. The tool comprises a blank having a shaft portion and a head portion. A single layer of grit comprising diamond crystals extends from the blank at substantially uniform height, said grit covering a predetermined proportion of the surface area of the head portion. A bonding material substantially surrounds the diamond crystals, forming micro-channels between the diamond crystals. The diamond crystal size is substantially less than other rapid cutting tools yet outperforms other tools in cutting speed, durability and smoothness of finish. The micro-channels are believed to both cool the dental tool and facilitate debris removal during use.

What is claimed is: 
     
       1. A dental rotary tool comprising:
 a blank having a shaft portion and a head portion; 
 a single layer of grit disposed upon the blank, the grit comprising at least one of spaced apart individual crystals and spaced apart clusters of crystals, the crystals extending to a generally uniform height above the surface of the blank, said grit covering less than about 90% of the surface area of the head portion; and 
 a bonding material that is generally limited to a fillet surrounding the crystals at the surface of the blank, thereby forming interconnected void spaces on the blank between the crystals, the interconnected void spaces providing continuous micro-channels for cooling the crystals and removing debris, the micro-channels extending to the surface of the head portion, said head portion having a thin film of bonding material and a thin film of bonding material on a portion of the sides of the crystals, the bonding material durably captivating the crystals to the blank while leaving a major portion of the crystals free of bonding material and available for cutting. 
 
     
     
       2. The dental rotary tool of  claim 1  wherein the grit comprises diamond crystals. 
     
     
       3. The dental rotary tool of  claim 1  wherein the grit comprises cubic boron nitride crystals. 
     
     
       4. The dental rotary tool of  claim 1  wherein the blank is made from a metal material. 
     
     
       5. The dental rotary tool of  claim 1  wherein the blank is made from a ceramic material. 
     
     
       6. The dental rotary tool of  claim 1  wherein the blank is made from a plastic material. 
     
     
       7. The dental rotary tool of  claim 1  wherein the bonding material comprises a braze composition. 
     
     
       8. The dental rotary tool of  claim 1  wherein the bonding material comprises a plated composition. 
     
     
       9. The dental rotary tool of  claim 8  wherein the plated composition is principally nickel. 
     
     
       10. The dental rotary tool of  claim 1  wherein the bonding material comprises a vitreous material. 
     
     
       11. The dental rotary tool of  claim 1  wherein the bonding material comprises a resinous material. 
     
     
       12. The dental rotary tool of  claim 1  wherein the bonding material comprises a glass material. 
     
     
       13. A dental rotary tool comprising:
 a blank having a shaft portion and a head portion; 
 a single layer of grit disposed upon the blank, the grit comprising at least one of spaced apart individual crystals and spaced apart clusters of crystals; and 
 a bonding material that is generally limited to a fillet surrounding the crystals at the surface of the blank, thereby forming interconnected void spaces on the blank between the crystals, the bonding material durably captivating the crystals to the blank while leaving a major portion of the crystals free of bonding material and available for cutting, 
 the uniformity of a cutting surface of the crystals being determined substantially by the size and aspect ratio of the grit. 
 
     
     
       14. The dental rotary tool of  claim 13  wherein the bonding material is an electroless material. 
     
     
       15. The dental rotary tool of  claim 13  wherein the bonding material is an electroplate material. 
     
     
       16. The dental rotary tool of  claim 13  wherein the grit comprises diamond crystals. 
     
     
       17. The dental rotary tool of  claim 13  wherein the grit comprises cubic boron nitride crystals.